pushfrontviewcontroler open blank screen

I need to set to root for second view controller through

SWRevealViewController

. But when I call

pushFrontViewcontroler

it become a blank screen. All my label that I defined in storyboard is missing. But the external xib i include is properly display. Am I missing something? Please enlighten me on how to solve this. Below is the code i use to call the second view controller.